Hach-Lange POLYMETRON 9240 Basic User Manual - Manual (Page 20)

13. The default values of the offset and slope are displayed along with the calculated values for the
last and current calibration.
14. A message is displayed indicating the success or failure of the calibration.
One point calibration
This process requires that a calibration solution of known sodium concentration is available. Refer to
Calibration solution concentrations on page 18 for information regarding the concentration of the
calibration solution.
1. Select the MAN.OFFSET CAL option to start the one point calibration process.
2. If necessary, enter the concentration of the calibration solution, and select START to initiate the
calibration process. Then, provided the reactivation frequency parameter is not zero (as is highly
recommended), the electrode is reactivated. On completion this is followed by a rinsing of the
overflow vessel.
3. When prompted, fill the overflow vessel with the calibration solution and select OK to start the
measurement.
4. The calibration solution is measured and the results displayed.
5. Once the final measurement is stable, the offset for the calibration is calculated.
6. A message is displayed indicating the success or failure of the calibration.
Two point calibration
This process requires that two calibration solutions of known sodium concentrations are available.
Refer to
Calibration solution concentrations on page 18 for information regarding the concentrations
of the calibration solution.
1. Select the MAN.OFFSET+SLOPE CAL option to start the two point calibration process.
2. If necessary, enter the concentrations of the calibration solution, and select START to initiate the
calibration process. Then, provided the reactivation frequency parameter is not zero (as is highly
recommended), the electrode is reactivated. On completion this is followed by a rinsing of the
overflow vessel.
3. The process is then very similar to the one-point calibration above, except after the instrument
measures the low value calibration solution, the overflow vessel will be rinsed and you will be
asked to fill it with the high value calibration solution.
4. A message is displayed indicating the success or failure of the calibration.
Automatic calibration setup
This allows the analyzer to be automatically calibrated at pre-defined and regular intervals.
The process is the same as described in
Calibrate known addition on page 19 except it is initiated
automatically at the pre-defined time.
1. Select the AUTO. CAL. SETUP option to access its sub-menu and set the calibration
parameters.
2. Turn the automatic calibration on or off by selecting Yes or No as appropriate. Note that even if
this is set to Yes, it is still possible to calibrate the analyzer manually if required.
3. CAL.SOL defines the concentration of the calibration solution. Refer to Calibration solution
concentrations on page 18 for information regarding the concentration of the calibration solution.
4. MODE can either be set up to a fixed date or to a specified Frequency.
5. If the mode is set to fixed date, enter the day(s) of the WEEK when the calibration will be
performed. Set the day to an asterisk to skip that day.
6. Set the HOUR field (HH:MM:SS format on a 24 hour clock) to the time the automatic calibration
should start.
20 English